Circuit breaker for ignition magnetos



De 9,.1924. 1,518,590 s. c. MCKEOWN CIRCUIT BREAKER FOR IGNITIONMAGNETOS v Filed Nov. 9, 1920 27 Z8 Q @2324 l/VVE/VTOR Samuel Ci/WcKeow/z ATTORNE Patented Dec. 9, 1924.

UNITED STATES PATENT OFFICE.

SAMUEL C. MCKEOWN, OF NEWARK, NEW JERSEY, ASSIGNOR TO SPLITDO'RFELECTRI- CAL COMPANY, OF NEWARK, NEW JERSEY.

CIRCUIT BREAKER FOR IGNITION MAG-NETOS.

Application filed November 9, 1920. Serial No. 422,787.

To all whom it may concern.

Be it known that I, SAMUEL G. M0- Known, a citizen of the United States,residing at Newark, in the county of Essex, State of New Jersey, haveinvented certain new and useful Improvements in Circuit Breakers forIgnition Magnetos, of which the following is a description, referencebeing had to the accompanying drawing and to the figures of referencemarked thereon.

This invention relates to circuit breakers for ignition ma netos forinternal combustion engines and especially to magnetos of theoscillatory type wherein a shaft bearing two lobes of constant polarityoscillates between two stationary pole pieces so that the flux threadingthe lobes is alternately passed through the pole pieces first in onedirection and then in the other. In this type of magneto an inductioncoil is generally wound about a bridge member joining the two polepieces. In the electrical circuit of the primary coil is intenposed acircuit breaker movable in unison with the engine so as to make andbreak the circuit at appropriate times. It is the common practice tomaintain this circuit closed until just prior to the time of firing acharge within a cylinder, then the circuit is opened, and the inducedcurrent in the secondary causes a spark to jump across the spark gapwithin the cylinders.

It is however a distinct disadvantage in a magneto and particularly in amagneto of the oscillatory type to keep the primary circuit closedduring the time when the flux is reversing and increasing. In an:oscillatory magneto this flux reversal and increase takes place duringthe so called cocking operation. As the lobes of the inductor of themagneto oscillate first into flux decreasing position and then intomaximum flux threading position, the rate of building up of flux in thedesired direction is diminished. by the counter magneto motive forcegener- Oil-Gd by the current in the coil of the vprimary circuit whichcurrent tends to main tain the old. direction of flux threading thecoil. As a consequence when the circuit is opened and there issimultaneously a rapid diminution of the flux threading the coil due tothe movement of the lobes from their maximum flux threading position totheir minimum flux threading position, the total decrease of the fluxand the consequent rate of change of flux is not as great as it mighthave been had the flux threading the coil been given the opportunity tobuild up to a greater magnitude.

It is an object of this invention to construct means whereby the fiuXmay build up to a higher value than has heretofore been possible inmagnetos of the type described.

As the speed of the engine increases and the periodicity of theoscillating shaft increases, the disadvantage of having a closed primarycircuit as is the common practice becomes more evident, since the timewithin which the flux is permitted to build up is shortened. It is,therefore, another object of this invention to provide means whereby a.higher engine speed may be used and still provide a good spark withinthe cylinders.

It is a further object of my invention to simplify the construction ofthe circuit breaker and make the same as of few parts as is consistentwith the proper functioning of the machine.

In the application of Leibing, Serial No. 312,426 filed July 21, 1919,now Patent 1,461,128, issued July 10, 1923, there is described one meanswhereby an intensified spark may be obtained. The present applicationdiscloses a new and improved means whereby the same result may begotten.

In the drawings which disclose one our bodiment of my invention:

Figure 1 is a view of my circuit interrupter, the magneto magneticcircuit being shown diagrammatically, the parts being in the normalposition, the circuit breaker and magneto operator being viewed fromdifferent ends of the magneto.

Figure 2 is a somewhat similar view showing the parts at the completionof the cocking operation, the circuit interrupter being closed, and therotor being about to return for its working stroke.

Figure 3 shows the rotor at the end of its working stroke, the contactsbeing then opened.

Figure 4 is a perspective view of one of the elements of an interrupterliiipping mechanism.

Referring now to the details, wherein like numbers refer tocorresponding parts in the various views, 1 and 2 illustrate the fieldpoles of a magnetic field structure across which the core 3 is placed.Core 3 is illustrated as having a low tension winding 4: and a hightension winding A spark gap 6 illustrating a plug in an engine cylinderis connected in circuit with the high tension winding The breaker box 7for attachment to one end of the ignition gei'ierator carries astationary insulated block 8 carrying an adjustable contact 9. A movablemember 10 carries a contact 11 adapted to cooperate with contact 9.Momber 10 is preferably grounded as indicated. Between the licld polesand 2 an inductor having lobes 12 and 13 is adapted to operate. Thistype oi inductor and its man ner of distributing the flux through thefield poles 1 and 2 and core 3 is illustrative of the well known Dixietype of ignition generator and since it is well illustrated anddescribed in Patent #:LOSlflGO, issued December 16, 1913, to C. T.Mason, it will not be further described herein except in con nectionwith my arrangement of control of the flux through the working coil.Attached to one end of theoperating shaft is a lever 14 which held in anormal stationary position by springs 15 and 1.6,all. in a well knownmanner. The lever 14( is adapted to be operated by a movable member 17driven by the engine. At the other end of the shaft is a member 18provided with a cam surface 19 adapted to engage a bumper 20 mounted onone end of the movable member and with a second cam surface 21 for amrpose hereinafter described. lVithin the breaker box 7 there is pivotedas at 22 acatch ,3 provided with a lip 24: to engage the end of themovable member carrying the contact and the lip is carved out at so asto litsnugly about the movable contact 11, in order that a good purchasemay be had on the movable member 10. It is understood that if thesupport for the movable contact be made longer that it would not benecessary to carve out the lip 25. A spring 26 trained around the pivot22 normally holds the catch so as to be in locking engagement with thecontact member when in its open position and a spring secured to a stud31 in the breaker box tends to hold the contacts 9 and 11 closed whenthe movable member released from the catch. The catch is dished on itsunder side at 27 and 28 so as to provide a clearance for the member 18,there being an inter'venin g ridge 29 between the dished portions 27 and28 for engagement with the cam surface 21 when the member 18 isoscillated into c'ir cuit breaker closing position.

Coming now to the operation of the device and assuming the parts to bein the normail or stationary position shown in Figure 1, it will benoted that the circuitbreaker points are held open by means of the catch23 and that the flux is threadin the coil in the direction of thearrows. the rotor ismoved by the member 17 rotating clockwise and actingto the right a 'ainst lever 14: it is seen that the lobes 12 and 13 asthey move counter clockwise toward the position shown in Figure 2 willproduce a change of flux tending to set up a current in the primarywinding 4. This current would op pose the decrease of flux in. onedirection and hinder the building up of flux in the opposite direction.But this is obviated by the circuit contacts 9 and 11 being held apart.As the lever 14 reaches the extreme cocked position shown in Figure 2the cam surface 21 ci'igages the ridge 29 on the catch 23 and thecontact member 10 is released Jen m-itting the contacts 9 and 11 toclose. This completes the so-called cocking ojieration. It should benoted that all the while that the flux has been reversing and buildingup that the contacts 9 and 11 were open and hence no hindrance oropposition. was offered by the primary coil to the reversal and thebuilding up of the flux. Vith the parts as shown in Figure 2, themagneto is ready for the working impulse. As the nose of the enginedriven member 17 passes from underneath the member 14., the springs 15and 16 snap the rotor around past the position in Figure 1 to aposition. as in Figure 3. At this time the catch 23 will hook over themember 10. The rotor then returns quickly to normal position shown inFigure 1.- The opening of the primary circuit takes place just after"the rotor lobes are leaving the pole pieces. that is, substantially atthe time when the maximum flux change takes place. Having thus describedmy invention what I claim is:

1. In a circuit breaker for an ignition current generator of theoscillating type, a stationary contact, a movable contact yieldinglyurged to closed position, a catch normally latching the movable contactin open posi tion' and a member rigidly connected with said oscillatoryelenmnt, oscillata-ble to alternately release said catch from contactclosing restraining movement and to more said movable contact tolatching position.

2. In a circuit breaker for an ignition current generatijir ot theoscillating typc, a stationary contact and a movable contact yleldinglyheld in engagement with the stationary contact a pivoted inentiber onwhich the movable contact is mounted, a men'iber rigidly connected withthe oscillatory element operable upon movement thereof in one directionto open said contacts, a catch operable to latch said movable member andmaintain said contacts open, said member being provided with means totrip said catch upon movement thereof in the opposite direction.

3. In circuit breaker for an ignition current generator of theoscillating type, a stationa'ly contact, a pivomily mounted mea ablecontact yieldingly held in; engagement therewith, a member rigidlyconnected with the oscillatory element, provided with a cam surface todisengage the contacts, a catch operable upon disengagement of thecontacts to latch the movable contact and hold the same open and asecond cam on said member operable upon movement of the member torelease the catch from contact moving restraining position.

4:. In a circuit breaker for an ignition current generator of theoscillating type, a stationary contact and a movable contact, a pivotedmember supporting the movable contact, a spring secured to said pivotedmember urging the contacts to closed position, a catch cooperating withthe movable contact to latch the contacts open, an oscillatable memberrigidly connected with the oscillatory element, provided with two camsurfaces, one cam surface acting to open the contacts upon oscillationof the member in one direction and the other cam surface acting to tripth catch to permit the contacts to close upon oscillation of the memberin the other direction.

5. In a circuit breaker for an ignition current generator of theoscillating type, a circuit breaker comprising a stationary contact, amovable contact yieldingly urged to closed position, a catch latchingthe movable contact in open position while the movable oscillatorymember is moving so as to reverse the flux in the magnetic circuit andto build the flux up therein in the opposite direction, and means at theend of said movement to trip said catch and close the contacts and meansoperative on the return movement of said oscillatory member to againopen said contacts.

6. In a circuit breaker for an ignition cur rent generator of theoscillating type, alatch for said circuit breaker, said circuit breakerbeing latched open during a flux reversal in the core of the generator,means to release said latch at the time of maximum flux threading thecore, and means to'cause said latch to again engage said circuit breakerimmediately after the time of maximum flux change in said core.

7. In a circuit breaker for an ignition current generator of theoscillating type, means normally latching the circuit breaker open, amember on the oscillatory element operable upon movement of said elementto maximum flux threading position to trip said first named means topermit the circuit breaker to close and means operative to restore theparts to normal position after the time of maximum flux change in saidcoil.

8. In a circuit breaker for an ignition current generator of theoscillating type, a stationary contact, a movable contact yieldinglyurged to closed position, a catch normally latching the movable contactin open position, while an oscillatable member is moving in onedirection and means actuated by said oscillatable member to release saidcatch from contact closing restraining movement, and means operative onthe return movement of said oscillatable member to again open saidcontacts.

9. In a circuit breaker for an ignition current generator of theoscillating type, a stationary contact and a movable contact, a pivotedmember supporting the movable con-- tact, a spring secured to saidpivoted member urging the contacts to closed position, a catchcooperating with the movable contact to latch the contacts open, amember actuated by the. oscillatable member and provided with two camsurfaces, one cam surface acting to open the contacts upon oscillationof the member in one direction and the other cam surface acting to tripthe catch to permit the contacts to close upon oscillation of the memberin the other direction.

In testimony whereof, I affix my signature.

AMUEL G. BICIQEOVN.

